Finishing machine



Filed Aug. 25, 1958 6 Sheets$heet 1 July 4, 1961 E. J. GUINN FINISHINGMACHINE 6 Sheets-Sheet 2 Filed Aug. 25. 1958 .Ezaniar f/don J.' Gain/7 vm N July 4, 1961 Filed Aug. 25, 1958 E. J. GUINN FINISHING MACHINE 6Sheets-Sheet 3 Eranfir E/a'on J Gui/7n MWMWW July 4, 1961 E. J. GUINNFINISHING MACHINE 6 Sheets-Sheet 4 Filed Aug. 25, 1958 H IE1 I .ExazzfirE/aan J Gui/m WW E July 4, 1961 E. J. GUlNN 2,990,655

' FINISHING MACHINE Filed Aug. 25, 1958 6 Sheets-Sheet 5 JI I 5 29 12 o6 1 6, l 5'9 I l d 1 6'0 o i 20 r I |l o Eran-fur Eldon J. Gui/7n fla 9July 4, 1961 E. J. GUINN FINISHING MACHINE 6 Sheets Sheet 6 Filed Aug.25, 1958 United SeesPar h O 2,990,655 FINISHING MACHINE Eldon J. Guinn,Detroit, Mich., assignor to Lyon Incorporated, Detroit, Mich., acorporation of Delaware Filed Aug. 25, 1958, Ser. No. 757,000 Claims.(Cl. 51-99) This invention relates generally to finishing machines, andmore specifically to an improved buffing machine which is particularlywell adapted to polish the interior of sink bowls.

Although the principles of the present invention may be included invarious buffing or polishing machines, a particularly useful applicationis made in a buffing machine such as is disclosed herein. In particular,when metal sinks, such as stainless steel, are fabricated from a sheetof metal, such fabrication is typically accomplished by a deep-drawingprocess. This process leaves tool'marks on the interior portion of thesink, which are unsightly. Heretofore, it has been common to removethese tool marks by hand or by using hand-held devices. This method hasbeen both tiresome and unwieldy. It has been impractical to increase thesize of buffer used so as to speed up the operation owing to the weightwhich the operator would have to hold.

The present invention contemplates the utilization of a base whichsupports the sink to be polished as well as the means for polishing thesink. The polishing means are provided with a source of power, and areadapted to be guided by hand over the surfaces of the article which areto be polished. Provision is made to releasably lock the workpiece in agiven position, and to releasably lock the bufiing element in a raisedor retracted position. Provision is also made for automatic starting andstopping of buffer movement in response to raising and lowering of thebutting element.

Accordingly, it is an object of the present invention to provide animproved bufling machine.

Another object of the present invention is to provide a bufling machinewhich may be manually guided over various surfaces of a workpiece whichis too large to hold by hand.

Yet another object of the present invention is to provide a buflingmachine, the buffing element of which automatically starts and stopsrotating in response to its position.

A still further object of the present invention is to provide a machinefor supporting and driving a relatively large buffing element, theweight of which is effectively balanced out.

Yet another objectof the present invention is to provide a buflingmachine having a buffing member which may be retracted and releasablylocked in a retracted position.

Yet another object is the provision of a buffing machine having movableelements whose relative friction is oppositely directed to the frictioncreated between the bufier and the workpiece.

A still further object of the present invention is the provision of abufiing machine which is adapted to releasably support a workpiece invarious bufling positions.

Another object of the present invention is the provision of a buffingmachine which is particularly suited to polish the interior of a sinkbowl.

Many other advantages, features and additional objects of the presentinvention will become manifest to those versed in the art upon makingreference to the detailed description and the accompanying sheets ofdrawings in which a preferred structural embodiment incorporating2,990,655 Patented July 4, 1961 2 the principles of the presentinvention is shown by way of illustrative example.

On the drawings:

FIGURE 1 is a side view of a bufiing machine provided in accordance withthe present invention, with the lower portion thereof omitted; I, v

FIGURE 2 is a top view of the bufiing machine shown in FIGURE 1;

FIGURE 3 is an end view of the lower portion of the machine as viewedfrom the right of FIGURES 1 and 2;

FIGURE 4 is an enlarged sectional view taken gener ally along line IV-IVof FIGURE 1;

FIGURE 5 is a perspective view of the machine shown in FIGURE 1, with aworkpiece disposed in the machine, the lower portion of the machinebeing omitted;

FIGURE 6 is a fragmentary perspective view of the machine shown inFIGURE 1 taken from the opposite side from that which FIGURE 5 is taken;and

FIGURE 7 is a fragmentary perspective view generally similar to FIGURE5, but in reduced scale and showing the lower portion of the machinewith the workpiece partially rotated.

7 As shown on the drawings:

The principles of this invention are particularly useful when embodiedin a bufiing machine assembly such as illustrated in FIGURE 1, generallyindicated by the numeral 10. The machine includes a base 11, a boom 12,an arm assembly 13, and a workpiece supporting table 14. As best seen inFIGURE 2, the base 11 is generally L-shaped, one leg of the L supportingthe table 14, and theother leg of the L being generally elevated asindicated at 11a, best seen in FIGURE 1.

The boom 12 is provided with a bearing block 16 which depends from itslower surface and which is secured to the boom 12 such as by screws 17.The upper level 11a of the base 11 supports a pair of journal blocks 18,19 while a shaft 20 extends through the journals 18 and 19 as well asthe bearing block 16. The shaft 20 is disposed horizontally so that theboom 12 may pivot about a horizontal axis extending through the shaft20. The bearing block 16 is secured to the boom 12 adjacent to one endthereof, so that the boom is inherently unbalanced. Remotely from theaxis of the shaft 20, there is secured a counterweight 21. A pair ofplates 22, 23 are secured as by welding to the boom 12 while atransverse pin 24 is in turn supported by the plates 22, 23. A doubleended hook 25 engages the pin 24 and a loop or eye 26 on thecounterweight 21 to secure the counterweight 21 to the boom 12.

To the upper surface of the boom 12, there is secured a pair of rails27, 28, each of which may be interrupted along its length as shown ifdesired. The rails 27 and 28 are disposed generally adjacent to thehorizontal axis extending through the shaft 20.

A second counterweight 29 is supported by the rails 27, 28, and isprovided with a means for selectably varying the distance between thecenter of mass of the counterweight 29 and the axis of the shaft 20. Tothis end, a shaft 30 is threadedly engaged by at least one of a pair ofsupports 31, 32 secured to the upper surface of the boom 12. The shaft30 is provided with a hand crank 33 at one end, and with a relativelyrotatable connection 15 at the other end with the counterweight 29. Thecrank 33 is so positioned that the boom 12 and the arm 13 are in agenerally balanced condition about they axis of the shaft 20.. Tofacilitate rocking of the boom 12 about the axis of the shaft 20,there-is provided a first handle 34 which in this embodiment is securednear the support 32 of the boom 12, the handle 34 thus being at the endof theboorn opposite to its pivoting axis.

Also at the end of the boom 12 opposite to the axis of the shaft 20,there is a second bearing block secured to the boom 12.

As best seen in FIGURE 4, the bearing block 35 is hollow and is securedas by a pair of screws 36 to the boom 12. A pair of bearings 37, 37 issupported by the block 35 and receives a second shaft 38 therethrough,the shaft 38 being rotatable about a second horizontal axis. The arm 13is supported adjacent to one end thereof by a pair of bearings 39, 39received and carried on the shaft 38 so that the arm 13 is disposed in alaterally offset relation with respect to the boom 12 and is alsorotatable about the second horizontal axis or shaft 38. The arm 13 isprovided with a second handle 40 which is secured to the arm 13 at apoint remote from the second horizontal axis. The handle 40 extends sothat its gripping portion is still further laterally offset with respectto the boom 12.

The other end of the arm remote from the bearings 39 is provided withmeans for rotatably supporting a buffer element 41. To this end, the arm13 is made hollow as shown and provided with a pair of axially spacedbearings 42, 42 through which a shaft 43 extends. The buffer 41 iscorotatable with the shaft 43 as is also a pulley 44. Suitable nuts,spacers, or washers are provided to hold the components together asshown. It is thus apparent that the buffer 41 is rotatable about a thirdhorizontal axis.

Referring again to FIGURES 1 and 2, it may be seen that the boom 12 isprovided with a horizontally directed pin 45 which is secured thereto ata point on the boom 12 remote from the arm 13 and on the other side ofthe first horizontal axis about which the boom 12 may be pivoted. Thereis also provided a lever system generally indicated by the numeral 46having a latch mechanism adapted to interlock generally with the boom 12and more specifically with the pin 45, at a point remote from the firsthorizontal axis. The lever system 46 includes a horizontal lever 47pivoted to the base 11 by a pin 48, a second horizontal lever 49 pivotedto the base 11 by a pin 50 and disposed near the bottom of the machine,together with a link member 51 which pivotably joins together the levers47 and 49. At one end of the lever system 46, and more particularly atthe free or rear end of the lever 47, there is provided an upwardlydirected hook 52 which has a generally upwardly and forwardly directedcam surface 53 which is adapted to engage the pin 45 when the boom 12 israised. The pin 45 earns the hook 52 out of the way to cause a pivotingof the lever 47 about the pin 48 until the pin 45 slips into the throatof the hook 52. This interengagement holds the handle end of the boom 12in a raised position, and holds the opposite end in a lowered positionas shown by the dash-dot lines in FIGURE 1. The other end of the lever49 is adapted to be actuated, to release the hook 52 from the pin 45. Tofacilitate this, the other end of the linkage and in particular theother end of the lever 49 is provided with a pedal portion 54 which maybe downwardly deflected to effect a retraction of the hook 52 todisengage it from the pin 45, thereby releasing the boom 12 so that itmay be lowered into a position to engage the workpiece S.

Referring further to FIGURES 1 and 2, it may be seen that power foroperating the bufiing machine 10 is provided by a motor 55 which issecured to a support plate 56 pivoted to the base 11a by a pin 57. Theplate 56 is provided with means to adjust its position or angle withrespect to the base, such means here comprising with the pivot pin 57 ascrew 58 having threaded engagement with the plate 56 and abuttingengagement with an upwardly directed stationary surface on the upperportion 11a of the base 11.

The motor 55 is provided with a driving pulley 59 which is rotatableabout an axis parallel to that of the shaft 20. The motor axis isvertically offset by the plate 56 from the axis of the shaft 20 by anamount which is determined by the position of the plate 56 with respectto the base 11. At least one belt 60 is directed about a driving pulley59 and thence about a second pulley 61 corotatably carried on the shaft38, in alignment with the driving pulley 59. As best seen in FIGURE 1,if the. motor 55 were lowered by adjustment of the plate 56, there wouldbe no significant change in the tension of the belt 60. However, if theboom 12 were rotated counterclockwise as shown in FIGURE 1, it can beseen that tension would be removed from the belt 60. The amount oftension which is lost by raising the boom 12, or which is gained bylowering the boom 12 is determined by the position of the motor 55 withrespect to the base 11. Thus lowering and raising the boom is effectiveto couple and to decouple, respectively, the pulleys 59 and 61.

Referring to FIGURE 4, it can be seen that the pulley 61, which iscorotatably coupled to the shaft 38, is also operative to effectrotation of an additional pulley 62 corotatably carried on the shaft 38.

The arm 13 is provided with a further pair of pulleys 63, 64 each ofwhich is bearingly supported on a shaft pin 65. The pulley 64 is anidler which acts to direct a belt 66 around a substantial portion of thepulley 62. The pulley 63 is supported by a slide plate 67 slidablyguided and supported in a channel 68 on the arm 13. The slide plate maybe secured in any selected position by conventional means (not shown) sothat the pulley 63 may be employed as a tensioning pulley for the belt66. Thus the belt 66, as best seen in FIGURE 1, extends between thepulleys 44 and 62, being guided in part by the pulley 64 and beingtensioned by the pulley 63. Thus rotation of the pulley 61 is effectiveto rotate the buffer 41.

Preferably, a belt guard 69 is provided for the belt 66, and a beltguard 70 is provided for the belts 60.

As best seen in FIGURES 6 and 7, the table 14 is provided with anest-like portion 71 which receives the bowl B of the sink S. The table14 is rotatably supported on the base 11, such as by a bearing assembly72, best seen in FIGURE 3. The bearing assembly 72 includes a lowerportion 73 which is supported by a transverse member 74 secured to thebase 11. The bearing assembly 72 includes an upper portion 75 secured tothe table 14. The bearing assembly 72 also includes a radial thrustportion 76 which carries part of the vertical load and which acts tocenter a pilot shaft 77 with respect to the bearing assembly 72.

In the instant embodiment, the buffer 41 has a length which enables itto extend to the left wall of the sink S as seen in FIGURE 3 and to theright beyond the center-line of the bearing assembly 72. Thus, when thetable is rotated about the bearing assembly 72, there will be a smallportion of the buffer 41 which engages a central portion of the sink Sfor either of two sink positions degrees apart from each other. Thus, solong as the buffer 14 can engage the sink S directly above the shaft 77,there will be no portion of the bottom of the sink not engaged by thebuffer 41, but there will be a small area of overlap between successivepasses of the buffer for different sink positions. This relationshipwill be maintained if the vertical axis of the shaft 77 or of thebearing assembly 72 is in a plane which is perpendicular to therotational axis of the buffer, and extends transversely through thebuffer.

A slide plunger 78 is slidably supported by a bracket 79 secured to thebase 11. The plunger 78 has a shoulder 80, here comprising a nut,against which a spring 81 acts. The other end of the spring 81 engages aportion of the bracket 79 or base 11 to act thereagainst so that thespring 81 may expand to urge the plunger 78 upwardly into lockinginterengagement with the table 14. The table 14 is provided with aplurality of openings or notches to receive the plunger 78, each suchopening or notch defining one angular position in which the table 14 maybe positively locked. As best seen in FIG- URE 7, the plunger 78 isprovided with a downwardly extending link 82 which is pivotally coupledto a lever 83 secured at one end by -a pin 84 to the base 11. The otherend of the lever 83 is provided with a pedal portion 85 by which theplunger 78 may be retracted to unlock the table 14 for rotation.

If desired, a switch assembly 86 may be disposed adjacent to the handle34 for starting and stopping the motor 55.

The motor 55 may be started or stopped with the boom 12 in any position.If the boom is in a raised position as shown in FIGURE 6, the drivingpulley 59 will slip with respect to the belts 60, whereby the buffer 41remains stationary.

After a sink has been disposed in the nest of the table 14 as shown inFIGURE 6, the pedal 54 may be actuated to release the hook 52 from thepin 45, thereby unlocking the boom for lowering about the shaft 20. Itmay be brought down by the right hand of the operator grasping thehandle 34. The amount of force needed is negligible since thecounterweight 29 can be positioned to make the mechanism substantiallyweightless, as it were. The operator may then grasp the handle 40 usinghis left hand, to guide the buffer 41 up and down across the furtherdisposed interior rear wall of the bowl B of the sink S, to guide thebuffer 41 back and forth across the bottom of the sink bowl, and toguide the buffer 41 up and down against the interior of the forward wallof the bowl.

After the desired degree of polish has been obtained, the table 14 maybe rotated after it has been unlocked by actuation of the pedal 85, andthus indexed, for example 180 degrees, so that the remainder of thesides of the bowl partially buffed may be finished. When the table isindexed to other positions 90 degrees from those described, the othervertical walls may be polished. It will be apparent that the flanges mayalso be polished by moving the arm back and forth across the forward orrearwardly disposed flanges.

When the buffer 41 engages the sink, there is a tendency for the bufferto be moved along the surface of the sink by the rotation of the buffer.This tendency is partially offset by the friction between the shaft 38and the bearings 39, which acts in the opposite direction.

It is to be understood that various lengths, shapes, and quality ofbuffer 41 may be attached to the shaft 43, as may be required by theworkpiece. V

The offsetting of the handle 40 with respect to the bandle 34 enablesthe operator to simultaneously grasp and manipulate each of suchhandles. At the same time, the operators hands are not required tounlock either of the boom 12 or the table 14, which unlocking may beeffected by the feet of the operator. Although various minormodifications might be suggested by those versed in the art, it shouldbe understood that I wish to embody within the scope of the patentwarranted hereon all such embodiments as reasonably and properly comewithin the scope of my contribution to the art.

I claim as my invention:

1. A machine for driving a rotary buffer comprising in combination: abase; a generally horizontally directed ,boom supported near one endthereof by said base and having a pivotal connection therewith forpivoting about a first horizontal axis which is disposed in offsetrelation below said boom in horizontally spaced relation to .said oneend; an arm pivotally supported adjacent to one end thereof by theopposite end of said boom and pivotable primarily about a secondhorizontal axis parallel to said first horizontal axis, the other end ofsaid arm having means-to rotatably support the rotary buffer forrotation about a third horizontal axis parallel to said horizontal axes;means carried by said arm for rotatably driving the buffer; acounterweight slidably supported by and above said boom adjacent to saidpivotal connecthereof; an arm pivotably supported adjacent to one end 1thereof by the opposite end of said boom, the other end of said armhaving means to rotatably support the rotary buffer; means carried bysaid arm. for rotatably driving the buffer; a pair of laterally spacedrails secured to the upper side of said boom above, adjacent to, andextending in horizontally spanning relation to said axis; acounterweight slidably supported on said rails; and means for selectablymoving said counterweight for varying the effective distance between thecenter of mass of said counterweight and said axis, said counterweightbeing movable through and beyond a point where said boom is balanced.

3. A machine for driving a rotary buffer comprising in combination: abase; a boom supported adjacent to one end thereof by said base andadapted to be pivoted about a horizontal axis; a lever linkage having alatch at one end thereof adapted to interlock with said boom remotelyfrom said axis when said boom is pivoted to a raised position and tohold said boom in the raised position, said latch being adapted to bedisengaged therefrom upon actuation of said linkage; an arm pivotablysupported adjacent to one end thereof by the opposite end of said boom,the other end of said arm having means to rotatably support the rotarybuffer; and means carried by said arm for rotatably driving the bulfer.

4. A machine for driving a rotary buffer comprising in combination: abase; a boom supported adjacent to one end thereof by said base andadapted to be pivoted about a horizontal axis; an arm pivotablysupported adjacent to one end thereof by the opposite end of said boom,the other end of said arm having means to rotatably support the'rotarybuffer; a horizontally directed pin secured to said boom remotely fromsaid arm and on the opposite side of said horizontal axis; a leversystem having a hook at one end thereof, said hook having a cam surfacedisposed to be engaged by said pin in response to raising of said boomto move said hook into a pin-engaging position for holding said boom ina raised position, the other end of said lever system being adapted tobe actuated to release said hook from said pin; and means carried bysaid arm for rotatably driving the buffer.

5. A machine for driving a rotary buffer comprising in combination: abase; a boom supported adjacent to one end thereof by said base andadapted to be pivoted about a first horizontal axis; an arm pivotablysupported adjacent to one end thereof by the opposite end of said boom,the other end of said arm having means to rotatably support the rotarybuffer; a driving pulley supported for-rotation about an axis slightlyvertically offset from said first horizontal axis; a second pulleyrotatably supported by said boom remotely from said first horizontalaxis and in alignment with said driving pulley; a belt having a lengtheifective to couple and decouple said pulleys in response to loweringand raising of said boom, respectively; and means connected to saidsecond pulley for 'rotatably driving the buffer in response to rotationof said second pulley.

6. A machine for driving a rotary buffer comprising in combination: abase; a boom supported adjacent to one end thereof by said base andadapted to be pivoted about a first horizontal axis; an arm pivotablysupported adjacent to one end thereof by the opposite end of said boom,the other end of said arm having means to rotatably support the rotarybuffer; a support plate pivoted to. saidv base; means for adjusting theangle between said plate and said base; a motor supported by said plateand having a driving pulley rotatable about an axis vertically offsetfrom said first horizontal axis by an amount determined by the angularposition of said support plate; a second pulley rotatably supported bysaid boom remotely from said first horizontal axis and in alignment withsaid driving pulley; a belt having a length effective to couple anddecouple said pulleys in response to lowering and raising of said boom,respectively; and means connected to said second pulley for rotatablydriving the buffer in response to rotation of said second pulley.

7. A machine for driving a rotary buffer comprising in combination: abase; a boom supported adjacent to one end thereof by said base andadapted to be pivoted about a first horizontal axis; an arm pivotablysupported adjacent to one end thereof by the opposite end of said boom,the other end of said arm having means to rotatably support the rotarybuffer; a support plate; means securing said plate to said base invarious selectable positions; a motor supported by said plate and havinga driving pulley rotatable about an axis vertically ofiset from saidfirst horizontal axis by an amount determined by the position of saidsupport plate; a second pulley rotatably supported by said boom remotelyfrom said first horizontal axis and in alignment with said drivingpulley; a belt having a length effective to couple and decouple saidpulleys in response to lowering and raising of said boom, respectively;and means connected to said second pulley for rotatably driving thebuffer in response to rotation of said second pulley.

8. A machine for driving a rotary buffer comprising in combination: abase; a boom pivotably supported adjacent to one end thereof by saidbase; an arm pivotably supported adjacent to one end thereof by theopposite end of said boom, the other end of said arm having means torotatably support the rotary buffer; a table for supporting the articleto be buffed, said table being rotatably secured to said base adjacentto said other end of said arm; a plunger slidably supported by said baseand biased into interlocking engagement with said table, said plungerbeing adapted to be retracted from said table to permit repositioning ofsaid table; and means carried by said arm for rotatably driving thebuffer.

9. A buffing machine for the interior of a sink bowl comprising incombination: a stationary base; a boom supported adjacent to one endthereof by said base and adapted to be pivoted about a first horizontalaxis; an arm supported adjacent to one end thereof by the opposite endof said boom and adapted to be pivoted about a second horizontal axis; arotary buffer supported by the other end of said arm for rotation abouta third horizontal axis while in engagement with the sink bowl; saidfirst, second, and third axes being parallel to one another; a table forsupporting the sink to be buffed; a bearing assembly securing said tableto said base for rotation about a fixed vertical axis, said verticalaxis lying in a vertical plane normal to said third horizontal axis andwhich Vertical plane extends transversely through said buffer for everyposition thereof; and means carried by said arm for rotatably drivingsaid buffer.

10. A bufiing machine for the interior of a sink bowl comprising incombination: a base; a boom supported adjacent to one end thereof bysaid base and adapted to be pivoted about a first horizontal axis; ashaft rotatably journalled by the opposite end of said boom for rotationabout a second horizontal axis; an arm rotatably supported adjacent tooneend thereof by said shaft in, a

laterally offset relation to said boom for pivoting about said secondaxis; a rotary buffer supported by the other end of said arm forrotation about a third horizontal axis while in engagement with the sinkbowl; a pair of laterally spaced rails secured to the upper side of saidboom adjacent to said first horizontal axis; a counterweight slidablysupported on said rails; means for selectably varying the distancebetween the center of mass of said counterweight and said first axis tobalance the torque of said boom, said arm, and said buffer about saidfirst axis; a first handle secured to said opposite end of said boom forpivoting said boom about said first horizontal axis; a second handlesecured to said arm remotely from said second horizontal axis anddisposed in further laterally offset relation from said boom; ahorizontally directed pin secured to said boom remotely from said armand on the opposite side of said first horizontal axis; a lever systemsecured to said base and having a hook at one end thereof, said hookhaving a cam surface disposed to be engaged by said pin in response toraising of said boom to move said hook into a pinengaging position forholding said boom in a raised position, the other end of said leversystem being adapted to be actuated to release said hook from said pin;a support plate pivoted to said base; means for adjusting the anglebetween said plate and said base; a motor supported by said plate andhaving a driving pulley rotatable about an axis vertically offset fromsaid first horizontal axis by an amount determined by the angularposition of said support plate; a second pulley corotatably carried bysaid shaft in alignment with said driving pulley, a belt having a lengtheffective to couple and decouple said pulleys in response to loweringand raising of said boom, respectively; means connected to said secondpulley for rotatably driving said buffer in response to rotation of saidsecond pulley; a table for supporting the sink to be buffed; a bearingassembly securing said table to said base for rotation about a verticalaxis, said vertical axis lying in a plane normal to said thirdhorizontal axis and which extends transversely through said buifer; anda plunger slidably supported by said base and biased into lockingengagement with said table, said plunger being adapted to be retractedfrom said table to permit repositioning said table.

References Cited in the file of this patent UNITED STATES PATENTS161,951 Gunn et al. Apr. 13, 1875 219,514 Plummer Sept. 9, 1879 236,824Morris Jan. 18, 1881 292,363 Rooney Jan. 22, 1884 306,772 Pratt et al.Oct. 21, 1884 709,020 Lahodny Sept. 16, 1902 729,667 Robinson June 2,1903 971,697 Smith Oct. 4, 1910 1,055,075 Philippi Mar. 4, 19131,100,704 Bartela June 23, 1914 1,462,420 Mikaelson et al July 17, 19231,795,262 Myers Mar. 3, 1931 2,405,468 Talboys Aug. 6, 1946 2,569,291Davis Sept. 25, 1951 2,651,888 Comstock Sept. 15, 1953 2,704,913Soderlund Mar. 29, 1955 2,718,732 Comstock Sept. 27, 1955 FOREIGNPATENTS 594,863 France July 4, 1925

